Reventlow traveled to several western European countries in the 1760s to study economic conditions. He returned to Denmark in 1770 and entered state service in 1773. He experimented with agrarian reform on the Lolland estates, which he inherited in 1775. In 1784 he was named head of the Rentekammeret Rentekammer (Exchequerdepartment of finance), with responsibility for agriculture.

On the basis of four earlier experiments he had conducted, Reventlow took measures to ease the lot of peasants who worked on crown serfsland. In 1786 he persuaded Crown Prince Frederick (later Frederick VI) to create an agrarian commission to study the conditions of the peasantry as a whole. The resulting reforms in 1787 and 1788 put an end to Danish serfdomled to the end of adscription, the legal bond between Danish peasants and the estate of their birth. Later measures of Reventlow led to clearly defined terms of voluntary peasant service on the large estates. Reventlow retired from public service in 1813 after being dismissed from his post.